It is frequently necessary to use hypodermic syringes for intravenous administration of fluids, or to withdraw fluids from the veins of a person during the course of treatment of an illness, or in routine diagnostic examinations. Hypodermic syringes used for this purpose are generally disposable, and are intended to be discarded after a single use by trained medical personnel.
These syringes are sometimes stolen from hospitals, or from medical equipment suppliers, or are not properly disposed of after being used by authorized personnel, and ultimately come into the possession of drug abusers. Although the medical community has long used disposable syringes a single time and then disposed of the used syringe, intravenous drug abusers consistently use the same syringe over-and-over again and share them with other drug abusers. This practice has led to the rapid spread of the HIV virus and Hepatitis in the drug user population.
Acquired Immune Deficiency Syndrome (AIDS) is now recognized as an epidemic of global proportion. In addition, there is an increasing recognition of a broad spectrum of severe HIV-associated diseases, including pneumonia, endocarditis, and pulmonary tuberculosis, especially among intravenous drug abusers.
Intravenous drug use is believed to account for most AIDS-related diseases in heterosexual men and women. This disease may also be transmitted to the children of infected adults, and to the sex partners of the infected persons, or to others, such as rescue personnel, who may be inadvertently exposed to the blood of the infected person.
As AIDS-related diseases continue to grow, it is becoming increasingly more important to control the means by which these diseases are transmitted, especially among groups associated with intravenous drug abuse. Since the major cause of spread of these diseases is through the repeated and/or shared use of contaminated hypodermic syringes and needles, a significant preventive measure would be the elimination of the ability of intravenous drug abusers to acquire syringes that could be used more than one time.
Examples of some prior art efforts to provide non-reusable syringes are disclosed in U.S. Pat. Nos. 3,478,937, 3,951,146, 4,367,738, 4,391,272, 4,493,703, 4,731,068 and 4,781,684. Most of these patented devices involve some type of catch mechanism which becomes engaged upon full or partial travel of the syringe piston to lock the piston in place and prevent either its withdrawal or its insertion into the syringe barrel. Other devices disclosed in thsese patents include pistons which become separated from the plunger or stem after an operating cycle to eject a fluid from the syringe. For instance, U.S. Pat. Nos. 4,391,272, 4,731,068 and 4,781,684 disclose arrangements in which both some type of catch mechanism and a separable piston and stem structure are used.
All of the prior art devices known to applicant are either excessively complicated and expensive in construction or are not adequately reliable in operation. Further, many prior art devices require either modification of the barrel, or the use of separate collars, adapters or sleeves to connect the piston to the plunger or stem. Moreover, it is possible in some of these devices to reassemble them after use, whereby they may then be repeatedly used.
Accordingly, it would be desirable to have a disposable hypodermic syringe that is reliable in operation, simple and economical in construction, and that is not capable of being reused after a single use.